Exhaust-gas turbocharger

ABSTRACT

An exhaust-gas turbocharger which has a radial bearing with a simple design which can quickly and easily be mounted. A pin/rolling roller arrangement is provided as the radial bearing. The pin is in this case fixed on the vane bearing ring. The rolling roller is placed onto the pin and, in the mounted state, an inner wall region of the unison ring is supported on the rolling roller mounted rotatably on the pin.

The invention relates to an exhaust-gas turbocharger according to thepreamble of claim 1.

In the case of such an exhaust-gas turbocharger, provision is made of avariable turbine geometry (VTG), in which guide vanes are adjusted bymeans of a unison ring. The unison ring is in this respect mountedcircumferentially by way of a radial bearing on the vane bearing ring.

It is an object of the present invention to provide an exhaust-gasturbocharger of the type indicated in the preamble of claim 1 which hasa radial bearing with a simple design which can quickly and easily bemounted.

This object is achieved by the features of claim 1.

According to the invention, a pin/rolling roller arrangement is providedas the radial bearing. The pin is in this case fixed on the vane bearingring. The rolling roller is placed onto the pin and, in the mountedstate, an inner wall region of the unison ring is supported on therolling roller mounted rotatably on the pin.

The dependent claims contain advantageous developments of the invention.

Claims 9 and 10 define a VTG cartridge according to the invention as anobject which can be marketed independently.

Further details, features and advantages of the invention becomeapparent from the following description of exemplary embodiments withreference to the drawing, in which:

FIG. 1 shows a schematically greatly simplified illustration of anexhaust-gas turbocharger according to the invention,

FIG. 2 shows a plan view of a first embodiment of a VTG cartridgeaccording to the invention,

FIG. 3 shows a perspective view of the VTG cartridge shown in FIG. 2,and

FIG. 4 shows a sectional partial illustration of the VTG cartridgeaccording to the invention shown in FIGS. 2 and 3.

FIG. 1 shows a schematically greatly simplified basic illustration of anexhaust-gas turbocharger 1 according to the invention, which has acharger axis of rotation L.

The exhaust-gas turbocharger 1 also has a turbine 2, which comprises aturbine wheel 3 surrounded by an intake duct 4, which is provided with aso-called VTG cartridge 5. This VTG cartridge 5 will be described indetail hereinbelow with reference to FIGS. 2 to 4.

The exhaust-gas turbocharger 1 also of course has all the other commonparts of an exhaust-gas turbocharger, such as a rotor 22, which ismounted rotatably in a bearing housing 21 and which bears the turbinewheel 3 at one end and a compressor wheel 24 of a compressor 23 at theother end. These parts are likewise shown only in schematically greatlysimplified form in FIG. 1, since they are not of importance forexplaining the principles of the present invention.

The VTG cartridge, which, as mentioned, will be explained in detailhereinbelow with reference to FIGS. 2 to 4, is likewise shown in greatlyschematically simplified form.

A VTG cartridge is understood to mean a structural unit which, between avane bearing ring 7 and a washer 6, delimits an intake duct 4 for thepassage of exhaust gases to the turbine wheel 3. Furthermore, a VTGcartridge 5 of this type has a plurality of vanes, which are arranged inthe intake duct 4 and of which FIGS. 3 and 4 show one vane designated 8as a representative example of all vanes bearing the correspondingreference numeral. The vanes 8 can be moved rotatably in the vanebearing ring 7 between a closed and an open position. For this purpose,the vanes 8 have vane shafts 9 each having an axis of rotation. The vaneshafts 9 in turn are connected to vane levers 10, of which two vanelevers are denoted in each case in FIGS. 2 and 3 with the referencenumeral 10. As FIGS. 2 and 3 show, the embodiment shown there has 10such, preferably cranked vane levers, in each case of identical design.

Each vane lever 10 has a lever head 11, which engages into an associatedgroove 12 in a unison ring 13. FIG. 2 above all shows in this respectthat the unison ring 13 surrounds the vane bearing ring 7 on theoutside, i.e. along the outer circumference thereof.

For radially mounting the unison ring 13, provision is made of a radialbearing, which according to the invention is formed by at least one pin14 fixed on the vane bearing ring 7. A rolling roller 15, against whichan inner wall region 16 of the unison ring 13 bears, is placed onto thepin 14.

The pin 14 is preferably butt-welded onto the vane bearing ring 7, whichis evident in particular from the illustration in FIG. 4, the pin 14having a small journal 17 which serves to ignite the arc upon weldingand in the process completely melts down, such that the pin 14 is joinedto the vane bearing ring 7 in an abutting manner.

A lock washer 18 is fixed to the free end 20 of the pin 14 and, in aparticularly preferred embodiment, is fastened to the end 20 of the pin14 at a distance A (see FIG. 4) from the upper side OS of the rollingroller.

As FIGS. 2 and 3 illustrate, in this particularly preferred embodiment atotal of three pin/rolling roller pairs denoted by the referencenumerals 14, 14′, 14″ and 16, 16′, 16″ are provided as the radialbearing. Furthermore, a lock washer 18, 18′, 18″ is of course assignedto each of these pairs.

Finally, FIGS. 3 and 4 show that the vane levers 10 have a cranked form,since the plane of the grooves 12 into which the lever heads 11 engageis offset in relation to the upper side of the vane bearing ring 7, asis evident in particular from FIG. 4.

In addition to the above written disclosure, reference is herebyexplicitly made to the illustrative representation of the invention inFIGS. 1 to 4 to supplement the disclosure of the invention.

LIST OF REFERENCE SIGNS

1 Exhaust-gas turbocharger

2 Turbine

3 Turbine wheel

4 Intake duct

5 VTG cartridge

6 Washer

7 Vane bearing ring

8 Vanes

9 Vane shafts

10 Vane lever

11 Lever heads

12 Grooves

13 Unison ring

14, 14′, 14″ Pin

15, 15′, 15″ Rolling roller

16 Inner wall region

17 Journal

18, 18′, 18″ Lock washer

19 Weld

20 End of the pin 14

OS Upper side

L Charger longitudinal axis

A Distance

1. An exhaust-gas turbocharger (1) having a turbine (2), which has a turbine wheel (3) surrounded by an intake duct (4), and a VTG cartridge (5), with a washer (6) and a vane bearing ring (7), which delimit the intake duct (4), a plurality of vanes (8), which are arranged in the intake duct (4) and are mounted in the vane bearing ring (7) by way of rotatable vane shafts (9), which are connected to vane levers (10), the lever heads (11) of which engage into associated grooves (12) in a unison ring (13), which surrounds the vane bearing ring (7) on the outside, and a radial bearing between the vane bearing ring (7) and the unison ring (13), wherein the radial bearing has at least one pin (14), which is fixed on the vane bearing ring (7) and onto which a rolling roller (15) is placed, against which an inner wall region (16) of the unison ring (13) bears.
 2. The exhaust-gas turbocharger as claimed in claim 1, wherein the pin (14) is butt-welded onto the vane bearing ring (7).
 3. The exhaust-gas turbocharger as claimed in claim 1, wherein a lock washer (18) is fastened on the free end (20) of the pin (14).
 4. The exhaust-gas turbocharger as claimed in claim 3, wherein the lock washer (18) is fastened on the free end (20) at a defined distance (A) from the upper side (OS) of the rolling roller.
 5. The exhaust-gas turbocharger as claimed in claim 3, wherein the lock washer (18) is fastened on the end (20) by means of a weld (19).
 6. The exhaust-gas turbocharger as claimed in claim 1, wherein the radial bearing has three pins (14, 14′, 14″) and rolling rollers (15, 15′, 15″) placed onto the latter.
 7. The exhaust-gas turbocharger as claimed in claim 6, wherein the pin/rolling roller pairs are arranged at identical angular distances circumferentially on the vane bearing ring (7).
 8. The exhaust-gas turbocharger as claimed in claim 1, wherein the vane levers (10) are cranked.
 9. A VTG cartridge (5) of an exhaust-gas turbocharger (1), having a washer (6) and a vane bearing ring (7), which delimit an intake duct (4), a plurality of vanes (8), which are arranged in the intake duct (4) and are mounted in the vane bearing ring (7) by way of rotatable vane shafts (9), which are connected to vane levers (10), the lever heads (11) of which engage into associated grooves (12) in a unison ring (13), which surrounds the vane bearing ring (7) on the outside, and a radial bearing between the vane bearing ring (7) and the unison ring (13), wherein the radial bearing has at least one pin (14), which is fixed on the vane bearing ring (7) and onto which a rolling roller (15) is placed, against which an inner wall region (16) of the unison ring (13) bears.
 10. The VTG cartridge as claimed in claim 9, wherein the pin (14) is butt-welded onto the vane bearing ring (7).
 11. The VTG cartridge as claimed in claim 9, wherein a lock washer (18) is fastened on the free end (20) of the pin (14).
 12. The VTG cartridge as claimed in claim 11, wherein the lock washer (18) is fastened on the free end (20) at a defined distance (A) from the upper side (OS) of the rolling roller.
 13. The VTG cartridge as claimed in claim 11, wherein the lock washer (18) is fastened on the end (20) by means of a weld (19).
 14. The VTG cartridge as claimed in claim 9, wherein the radial bearing has three pins (14, 14′, 14″) and rolling rollers (15, 15′, 15″) placed onto the latter.
 15. The VTG cartridge as claimed in claim 14, wherein the pin/rolling roller pairs are arranged at identical angular distances circumferentially on the vane bearing ring (7).
 16. The VTG cartridge as claimed in claim 9, wherein the vane levers (10) are cranked. 